From 828b9644ccb210de43bdc93a882a1de7440e8226 Mon Sep 17 00:00:00 2001
From: ikpil <ikpil0@gmail.com>
Date: Sun, 7 Jul 2024 12:38:09 +0900
Subject: [PATCH] Changed agents management from list to dictionary in `Crowd`

---
 CHANGELOG.md                               |  1 +
 src/DotRecast.Detour.Crowd/DtCrowd.cs      | 37 ++++++++++++++--------
 src/DotRecast.Detour.Crowd/DtCrowdAgent.cs |  2 +-
 3 files changed, 25 insertions(+), 15 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index a83a32f..19725c9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -22,6 +22,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Changed to use Span<byte> and stackalloc for improved performance and memory management in `RcLayers.BuildHeightfieldLayers()`
 - Changed vertCount and triCount to byte in `DtPolyDetail`
 - Changed `new float[]` to `stackalloc float[]` in `DtConvexConvexIntersections.Intersect()`
+- Changed agents management from list to dictionary in `DtCrowd`
 
 ### Removed
 - Removed RcMeshDetails.VdistSq2(float[], float[])
diff --git a/src/DotRecast.Detour.Crowd/DtCrowd.cs b/src/DotRecast.Detour.Crowd/DtCrowd.cs
index e8d83c1..184b718 100644
--- a/src/DotRecast.Detour.Crowd/DtCrowd.cs
+++ b/src/DotRecast.Detour.Crowd/DtCrowd.cs
@@ -120,8 +120,9 @@ namespace DotRecast.Detour.Crowd
     /// @ingroup crowd
     public class DtCrowd
     {
-        private readonly RcAtomicInteger _agentId = new RcAtomicInteger();
-        private readonly List<DtCrowdAgent> _agents;
+        private readonly RcAtomicInteger _agentIdx;
+        private readonly Dictionary<int, DtCrowdAgent> _agents;
+        private readonly List<DtCrowdAgent> _activeAgents;
 
         private readonly DtPathQueue _pathQ;
 
@@ -170,7 +171,9 @@ namespace DotRecast.Detour.Crowd
             // Allocate temp buffer for merging paths.
             _maxPathResult = DtCrowdConst.MAX_PATH_RESULT;
             _pathQ = new DtPathQueue(config);
-            _agents = new List<DtCrowdAgent>();
+            _agentIdx = new RcAtomicInteger(0);
+            _agents = new Dictionary<int, DtCrowdAgent>();
+            _activeAgents = new List<DtCrowdAgent>();
 
             // The navQuery is mostly used for local searches, no need for large node pool.
             SetNavMesh(nav);
@@ -235,11 +238,10 @@ namespace DotRecast.Detour.Crowd
         /// @return The index of the agent in the agent pool. Or -1 if the agent could not be added.
         public DtCrowdAgent AddAgent(RcVec3f pos, DtCrowdAgentParams option)
         {
-            int idx = _agentId.GetAndIncrement();
+            int idx = _agentIdx.GetAndIncrement();
             DtCrowdAgent ag = new DtCrowdAgent(idx);
             ag.corridor.Init(_maxPathResult);
-            _agents.Add(ag);
-
+            AddAgent(ag);
             UpdateAgentParameters(ag, option);
 
             // Find nearest position on navmesh and place the agent there.
@@ -278,15 +280,22 @@ namespace DotRecast.Detour.Crowd
             return ag;
         }
 
-        /**
-     * Removes the agent from the crowd.
-     *
-     * @param agent
-     *            Agent to be removed
-     */
+        // Add the agent from the crowd.
+        public void AddAgent(DtCrowdAgent agent)
+        {
+            if (_agents.TryAdd(agent.idx, agent))
+            {
+                _activeAgents.Add(agent);
+            }
+        }
+
+        // Removes the agent from the crowd.
         public void RemoveAgent(DtCrowdAgent agent)
         {
-            _agents.Remove(agent);
+            if (_agents.Remove(agent.idx))
+            {
+                _activeAgents.Remove(agent);
+            }
         }
 
         private bool RequestMoveTargetReplan(DtCrowdAgent ag, long refs, RcVec3f pos)
@@ -358,7 +367,7 @@ namespace DotRecast.Detour.Crowd
      */
         public IList<DtCrowdAgent> GetActiveAgents()
         {
-            return _agents;
+            return _activeAgents;
         }
 
         public RcVec3f GetQueryExtents()
diff --git a/src/DotRecast.Detour.Crowd/DtCrowdAgent.cs b/src/DotRecast.Detour.Crowd/DtCrowdAgent.cs
index efb465b..613f1c6 100644
--- a/src/DotRecast.Detour.Crowd/DtCrowdAgent.cs
+++ b/src/DotRecast.Detour.Crowd/DtCrowdAgent.cs
@@ -28,7 +28,7 @@ namespace DotRecast.Detour.Crowd
     /// @ingroup crowd
     public class DtCrowdAgent
     {
-        public readonly long idx;
+        public readonly int idx;
 
         /// The type of mesh polygon the agent is traversing. (See: #CrowdAgentState)
         public DtCrowdAgentState state;